As a device for measuring a distance from a subject device to an object without contact, a time of flight (TOF: time of flight) distance measurement device is provided. The time-of-flight distance measurement device emits a modulated light (distance measuring light) modulated in a pattern having a repetitive period toward a space, and receives an incident light containing a reflected light obtained by reflecting the modulated light on an object. The time-of-flight distance measurement device distributes charges corresponding to the received incident light to multiple storage capacitors and accumulates the distributed charges, and measures a distance from the subject device to the object by using a sampled value (for example, refer to Patent Literatures 1 to 4).
In the time-of-flight distance measurement device, a distance error is required to be reduced. As methods for reducing the distance error, there are a method of suppressing a phase angle error, that is, increasing a signal-to-noise ratio (SNR: signal-to-noise ratio) and a method of increasing a modulation frequency. In a method of increasing the SNR, a light emission power is increased in order to increase a signal component, an optical filter is used to reduce the noise component, and the number of integrations is increased to increase the SNR. As a conventional art for increasing the light emission power, a technique for emitting a light in a burst mode is disclosed (for example, refer to Non Patent Literature 1).